ML20211J037
| ML20211J037 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 10/31/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20211J030 | List: |
| References | |
| TAC-61283, TAC-61284, NUDOCS 8611100180 | |
| Download: ML20211J037 (6) | |
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,h SA_FETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENTS NOS.132 AND 66 TO FACILITY OPERATING LICENSES NOS. DPR-57 AND NPF-5 GEORGIA POWER COMPANY OGLETHORPE POWEa CORPORATION MUNICIPAL ELECTRIC A fHORITY OF GEORGIA CITY OF DALTON, GEORGIA EDWIN I. HATCH NUCLEAR PLANT, UNITS NOS. 1 AND 2 DOCKETS NOS. 50-321 AND 50-366
1.0 INTRODUCTION
By letter dated April 15,1986 (Reference 1) Georgia Power Company (GPC) proposed to change the Technical Specifications (TS) for the Edwin I. Hatch Nuclear Plant Units 1 and 2 in four areas. These areas are related to (1) requirements for.the Red Worth Minimizer (RWM) and the Rod Sequence Control l
System (RSCS), (2) restrictions on the fuel to be stored in the spent fuel l
pools, (3) additions to the Maximum Average Planar Linear Heat Generation j
Rate (MAPLHGR) limit curves for several new fuel assemblies, (4) editorial l
changes to correct editorial errors and to clarify applicability of limits to
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various fuel assembly types. The initial submittal was supplemented by additional information (Reference 2) in response to staff questions. These l
requests are further described as follows.
i 1.
It is proposed that the use of Technical Specification requirements for RWM and RSCS be modified to permit the use of Banked Position Withdrawal Sequences (BPWS) for the first 50 percent of control rod withdrawal.
This modified pattern would be enforced by the RWM alone in this regime. The RWM and RSCS would continue to enforce the Group Notch pattern above 50 percent rod withdrawal as in the past. This mode of operation has been discussed in Amendment 12 to GESTAR II (Reference 3) and in the staft Safety Evaluation Report on this subject (Reference 4).
Its chief advantage to the utility is that with BPWS a limiting generic analysis may be used for the Rod Drop Accident (RDA) analysis 8611100180 861'031 I
l DR ADOCK 0500 1
.f and a reactor-cycle specific analysis is not needed.
From an NRC viewpoint it provides smaller rod reactivity worths should a RDA event occur.
In Reference 2 GPC responded to staft questions on maximal use of the RWM in the BPWS withdrawal range and to the quality control aspects of the use of second operators when the RWM is not operational.
It is noted that the BPWS has been procedurally implemented for several years at Hatch (without RDA credit) and the experience with the RWM has resulted in high reliability and minimum bypass. When required, the second operator procedures and quality control has been substantially examined and improved over the past several years as a result of a previous enforcement action relating to control rod operation.
2.
GPC proposes to remove from Section 5 of the TS relating to the spent fuel pool the fuel assembly linear mass restrictions of 15.2 grams of Uranium-235. per centimeter. Also proposed is the removal from Section 5 of other descriptions of mechanical features of the. fuel assemblics that nay be in the core.
General. Electric (GE) now provides in GESTAR II (Reference 5) a staff approved approach to fuel assembly limits in the spent fuel pool based on k-infinity of the assemblies, without specific regard to linear mass limits. GESTAR II provides specific k-infinity limits for assemblies (of GE Jesign) to be stored in spent fuel racks of GE design in order to maintain a (staff approved) fuel pool multiplication limit of less than 0.95, including uncertainties. Maximum k-infinities for each GE fuel design are also given. Hatch spent fuel racks are GE designed high-density racks and as such have a k-infinity limit of 1.33 for GE fuel according to Amendment 13 to GESTAR II (Reference 6). Current Hatch fuel assemblies are all of GE design.
In addition to the changes relating to linear mass requirements, changes are also proposed for descriptions of fuel assemblies in the core which would eliminate specific mechanical descriptions (e.g., 62 rods) and i
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refer instead to assemblies analyzed with NRC approved methods and which comply with Design Bases in the Hatch Final Safety Analysis Report
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(FSAR).
3.
'GPC proposed to add new-fuel types and channel thickness to its inventory. This requires additional MAPLHGR curves for the TS. These i
fuel assemblies have been analyzed for the Loss-of-Coolant Accident event and resulting MAPLHGR limits for Hatch by GE using NRC approved
. methods (see Attachment 2 to Referen'ce 1). The results are applicable
- to both Hatch I and 2 The MAPLHGR results are applicable to assemblies,
P8DRB283, BP8DRB283 and BP8DRB299 with 80 mil channel thicknesses which are added to the-Hatch 1 and 2 TS.
4.-
GPC proposed two editorial changes for Hatch 2 to correct a typographical error in Basis Table 3.2.1-1 and a title change.to (new) Figure 3.2.1-12.
There are also editorial changes to MAPLHGR figures for both units to specify which thermal limits apply to which channel thickness and to
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barrier or nonbarrier fuel. There are also some figure number changes because of the added MAPLHGR curves.
2.0 EVALUATION i=
- 1.
A previous generic review (Reference ~4) has concluded that-the use of a j.
RWM enforced BPWS pattern for the first 50 percent of rod withdrawal in.
I a Group' Notch RSCS plant is acceptable and in fact preferab.le, and i
plants making the change will be able to take credit for the statistical analysis of the RDA and will not have to analyze the event for reloads.
- This approval is applicable to Hatch I and 2 upon adoption of the BPWS procedures.
To permit the procedures, TS changes are made to Specifications 3/4.3.G (and Basis 3/4.3.G) for Hatch I and to 3/4.1.4.1 and.2 for Hatch 2.
i These changes appropriately address RWM enforced BPWS patterns for the i
first 50 percent-and RWM and RSCS enforced Group Notch beyond 50 percent withdrawal. They are acceptable.
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O me i UPC response to questions on RWM operability and second operator effectiveness indicate that, as a result of previcus implementation of UPWS patterns and a previous problem with rod movement error resulting in Enforcement Action, particular special attention has been given to these areas for several years. This attention appears to have resulted in appropriate procedure and quality control examination and. improvement in these areas, and the response is acceptable.
2.
The removal of previous requirements for a U235 linear mass limit for the spent fuel pool has become generally accepted practice. This change is based on the staff approval of the GE approach (described in GESTAR II) of determining, for a given fuel pool design, limits on the k-infinity of fuel assemblies which may.be placed in the pool racks, and providing for each GE fuel assembly design a maximum k-infinity which can exist over the fuel burnup range. This change from the U235 content limit results from the recognition of the reactivity effect of the gadolinium burnable poison in the fuel assembly. The basic requirement for the fuel pool, that the neutron multiplication remain less than 0.95, remains unchanged.
For Hatch the (Section 5) TS limit of 0.95 remains and the corresponding basis will refer to the GESTAR II description of the approach and limits. Current and presently planned future Hatch fuel is described in the current GESTAR II (Revision 7) and the (approved) assembly k-infinity values are within the limit for the l
GE designed Hatch high density racks. The proposed approach and TS l
change is thus acceptable for Hatch I and 2, when using GE fuel. The
. methodology for determining k-infinity of assemblies by other fuel vendors would require further review.
The proposed change to the TS Section 5 description of mechanical
' features of fuel assemblies in the core eliminates a few not very useful descriptive terms and provides instead a requirement to use assemblies which have been analyzed with NRC approved methods and which comply with Safety Design Bases given in the Hatch FSAR. This is a reasonable change and is acceptable.
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o 3.
The new MAPLHGR curves for the new fuel assembly or new channel thickness proposed to be added to the Hatch I and 2 inventories have been calculated with NRC approved standard methodology by GE for Hatch 2, and since Hatch 2 results are conservative for Hatch 1 (Attachment 2 to Reference 1), they are also applicable for Hatch 1.
These additions to the Hatch TS are therefore acceptable. They will be Figures 3.11.1 Sheets 5 and 6 for Hatch 1 and 3.2.1-10 and 11 for Hatch 2.
4.
The editorial changes to correct a typographical error, retitle a figure, change page number and specify channel thickness and barrier fuel more clearly are all straightforward and acceptable.
We have reviewed the report and supplemental information submitted by GPC for proposed TS changes relating to BPWS operation, spent fuel pool limits, new MAPLHGR curves and editorial alterations.
Based on this review we have concluded that appropriate material was submitted and that the proposed changes satisfy, staff positions and requirements in these areas. Operations in the proposed manner and the TS changes are acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
i An Environmental Assessment has been prepared pursuant to 10 CFR Par't 51.32 and published in the Federal Register on
4.0 CONCLUSION
On the basis of the considerations discussed above, the staff has concluded that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations.
l Principal Contributor:
H. Richings i
Dated: October 31, 1986
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REFERENCES 1.
Letter (and Enclosures) from J. T.-Beckham, Georgia Power Company (GPC),
to D. Muller, NRC, dated April 15, 1986, "Edwin I. Hatch Nuclear Plant
[
. Units 1 and 2 Technical Specifications Revisions...."
2.
Letter from L. T. Gucwa, GPC, to D. Muller, NRC, dated July 25, 1986,
".... Supplemental Information."
3.
Letter (and Enclosure) from J. Charnley, GE, to C. Thomas, NRC, Dated May 17, 1985, " Proposed Amendment 12 to GE Licensing Topical Report NLDE-24011-P-A."
4.
Letter from C. Thomas, NRC, to J. Charnley, GE, dated October 11, 1985, 1
" Acceptance for Referencing of.... NEDE-24011-P-A,.... Revision 6, Amendment 12."
5.
NEDE-24011-P-A (GESTAR II),- Revision 7 August 1985, " General Electric Standard Application for Reactor Fuel."
i 6.
NEDE-24011-P-A (GESTAR II), Revision 6 Amendment 13.
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